Gulcin Turkmen Sariyildiz,1,2 Canan Cicek Demir,3 Mehmet Emin Demir,4,5 Aykut İlker Arslan,6 Oktay Banli,7 Ali Doğan Dursun8 1Operating Room Services, Vocational School of Health Services, Atilim University, Ankara, Turkey; 2Department of General Surgery, Medicana International Ankara Hospital, Ankara, Turkey; 3Department of Endocrinology, Internal Medicine, Faculty of Medicine, Atilim University, Ankara, Turkey; 4Department of Nephrology, Internal Medicine, Faculty of Medicine, Atilim University, Ankara, Turkey; 5Department of Nephrology, Medicana International Ankara Hospital, Ankara, Turkey; 6Department of Medical Microbiology, Faculty of Medicine, Atilim University, Ankara, Turkey; 7Department of General Surgery, Ankara Obesity Surgery Clinic, Ankara, Turkey; 8Department of Physiology, Faculty of Medicine, Atilim University, Ankara, TurkeyCorrespondence: Ali Doğan Dursun, Atilim Universitesi Ahlatlibel Kampusu, Saglik Hizmetleri Meslek Yuksek Okulu, 1835. Caddesi No. 5, Cankaya, Ankara, 06805, Turkey, Tel +90 312 586 6902 ; +90 533 211 4821, Email ali.dursun@atilim.edu.tr; alidogandursun@gmail.comBackground: The excessive accumulation of fat tissue in obesity is the source of chronic low-level inflammation and causes future dysmetabolic and cardiovascular disorders. Removal of this excessive fat tissue with the aid of bariatric surgery (BS) techniques, such as sleeve gastrectomy, may reverse adverse inflammatory outcomes. The aim of this study is to investigate the impact of sleeve gastrectomy on inflammatory markers, specifically endocan, IL-6, and CRP, in individuals with obesity.Methods: Thirty-two patients with class 3 obesity and class 2 obesity + comorbidities were enrolled in the study. Clinical characteristics including age, comorbidity, body mass index (BMI), waist, and hip circumferences of the participants were noted before and 3 months after sleeve gastrectomy. Blood samples were collected during those periods to assess biochemical features such as serum endocan, interleukin-6 (IL-6), C-reactive peptide, fasting insulin, glycosylated hemoglobin A1c levels, and lipid panel. A statistical package program was used for the analysis of those parameters, and p< 0.05 was accepted as significant at a 95.0% confidence interval.Results: BMI reduced from 43.55± 6.78 to 36.16± 6.14 kg/m2 within 3 months following BS (p< 0.001). Preoperative serum endocan, IL-6, and CRP levels were correlated with BMI, and in line with BMI reduction, their serum levels decreased after BS (p< 0.05). HOMA-IR also reduced after BS, and both in the pre and post-BS periods correlated with BMI, IL-6, endocan, and CRP levels (p< 0.05). The mean total body weight loss was 20.4% within 3 months post-BS.Conclusion: BS techniques are effective in weight loss and reversing the inflammatory processes caused by obesity. Serum endocan, IL-6, and CRP levels are promising markers for describing obesity-related inflammation and objectively checking the alleviation of inflammation following BS.Keywords: bariatric surgery, endocan, interleukin-6, sleeve gastrectomy, weight loss